Penicillin Discovered — 97 Years Ago

A Messy Lab and a Lucky Mold

In September 1928, Scottish bacteriologist Alexander Fleming returned from a holiday to find one of his petri dishes had been contaminated by mold. Instead of throwing it away, he looked more closely. Around the mold — later identified as Penicillium notatum — bacteria were dying. Fleming had accidentally discovered the world's first antibiotic. He published his findings but struggled to isolate the active compound, and the discovery sat largely unused for over a decade.

From Lab Curiosity to Life-Saver

In 1940, Oxford scientists Howard Florey and Ernst Chain figured out how to purify penicillin in usable quantities. Their first patient, a police officer dying from a blood infection, began recovering after just one day of treatment — then relapsed and died when the team ran out of penicillin. The US and UK governments fast-tracked mass production in time for D-Day in 1944. By the end of World War II, penicillin was saving thousands of lives a week.

The World Before Antibiotics

Before penicillin, a scratch from a rose thorn could kill you. Strep throat was a death sentence. Pneumonia, syphilis, and wound infections killed millions annually. Fleming, Florey, and Chain shared the Nobel Prize in 1945. Fleming warned even then about antibiotic resistance — bacteria evolving to defeat the drugs. That warning is more urgent today than ever. The date calculator shows just how recently humans lived without this protection.